Ticino Sopraceneri
Obere Maggiatäler
Updated off-schedule
The provider reissued this bulletin at 23 Oct 15:00 UTC, outside the normal publication cycle.
Avalanche Problems
Wind slab
2-
Field notes
Look for fresh snow deposits on Slope facing downwind/ wind sheltered aspect. Snow deposits can attain several times average snow depth.EAWS glossary, in Usually a steep, elongated, eroded trench; typically prone to snowdrift accumulation.EAWS glossary and Rounded or elongated concavity; typically tending to accumulate snowdrift.EAWS glossary, and behind ridgelines and abrupt changes in terrain — these are where the wind has loaded the snow into slabs that are easy to trigger. Recent avalanches, shooting cracks under your weight, and Distinctive noise (resembling a “whumpf” sound) occurring when a weak layer beneath a slab collapses. The air of the weak layer is forced outside the snowpack, with the resulting whumpf sound being heard. The sound usually indicates an unstable situation and can be accompanied by surface cracking. A whumpf is a clear avalanche alert.EAWS glossary sounds are clear confirmations of the problem. The safest move is to avoid wind-loaded terrain entirely. NB wind signs alone don't always mean an avalanche problem exists, and the age of drifted snow is hard to judge.
Snowpack & Weather
Snowpack
In Areas above approximately 3000 m (particularly glaciated areas).EAWS glossary, the new snow and wind-drifted snow are mostly being deposited on a continuous Snow deposited on the ground in a multiplicity of layers.EAWS glossary. The greatest snow depths are already found along the main Alpine ridge from the Monte Rosa region to the Bernina region. Especially there, faceted Snowpack layer in which the crystals are poorly bonded and the layer has the potential to fail. Typical crystals in dry weak layers causing avalanches are : precipitation particles; surface hoar; faceted crystals; hollow crystals; graupel. Generally >1mm in size, loose grains with few bonds Wet weak layers can be formed by all snow crystal/grain types.EAWS glossary are partly present in the Snow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary, so that fractures at the interface between the old and new snow are possible. Elsewhere, weak layers are to be expected mainly within the different layers of new snow and wind-drifted snow.
Outlook
Sunday
On Sunday, skies will be heavily overcast in the north, with widespread precipitation. Precipitation amounts are uncertain. Along the northern Alpine ridge and in Valais, 20 to 40 cm of fresh snow are possible at high altitudes. The snowfall level will rise from 1500 m to around 2600 m during the night leading into Sunday. In the south, it will remain mostly dry with sunny intervals. Strong to storm-force winds will blow from westerly directions.
As the snowfall level rises, the Snow deposited on the ground in a multiplicity of layers.EAWS glossary will become moist or wet up to high altitudes. Increasing numbers of small and medium-sized wet loose snow avalanches are to be expected. With new snow and wind the danger of dry avalanches will increase slightly in Areas above approximately 3000 m (particularly glaciated areas).EAWS glossary.
Monday
On Monday, skies will be cloudy at times in the north, otherwise mostly sunny. The zero degree level will rise to above 3000 m during the day. Light to moderate winds will blow from westerly directions.
The danger of dry avalanches will decrease, but only slowly in Areas above approximately 3000 m (particularly glaciated areas).EAWS glossary. With solar radiation, moist loose snow slides and avalanches are to be expected on steep slopes in high alpine regions. In addition to the danger of burial, particular attention should also be paid to the danger of being swept along and falling.
Source
Issued
23 Oct 15:00 UTC
Valid until
24 Oct 15:00 UTC
Next update
24 Oct 15:00 UTC
Schedule
Off-schedule